2. Outline What is PHP? History of PHP Why PHP ? What is PHP file? What you need to start using PHP ? Syntax PHP code. echo & print Statement Variables. Data Types. Constants &Operators. Conditional Statements & Loops.

3. What is PHP?  Personal Homepage Tools/Form Interpreter  PHP is a Server-side Scripting Language designed specifically for the Web.  An open source language  PHP code can be embedded within an HTML page, which will be executed each time that page is visited.

4. What is PHP? (cont’d) Interpreted language, scripts are parsed at run-time rather than compiled beforehand Executed on the server-side Source-code not visible by client ‘View Source’ in browsers does not display the PHP code Various built-in functions allow for fast development Compatible with many popular databases

5. History of PHP PHP (PHP: Hypertext Preprocessor) was created by Rasmus Lerdorf in 1994. It was initially developed for HTTP usage logging and server-side form generation in Unix. PHP 2 (1995) transformed the language into a Server-side embedded scripting language. Added database support, file uploads, variables, arrays, recursive functions, conditionals, iteration, regular expressions, etc. PHP 3 (1998) added support for ODBC data sources, multiple platform support, email protocols (SNMP,IMAP), and new parser written by Zeev Suraski and Andi Gutmans. PHP 4 (2000) became an independent component of the web server for added efficiency. The parser was renamed the Zend Engine. Many security features were added. PHP 5 (2004) adds Zend Engine II with object oriented programming, robust XML support using the libxml2 library, SOAP extension for interoperability with Web Services, SQLite has been bundled with PHP

6. Why PHP ?  PHP runs on different platforms (Windows, Linux, Unix, Mac OS X, etc.)  PHP is compatible with almost all servers used today (Apache, IIS, etc.)  PHP has support for a wide range of databases  PHP is free. Download it from the official PHP resource: www.php.net  PHP is easy to learn and runs efficiently on the server side

7. What does PHP code look like? Structurally similar to C/C++ Supports procedural and object-oriented paradigm (to some degree)

8. What Can PHP Do?  PHP can generate dynamic page content  PHP can create, open, read, write, and close files on the server  PHP can collect form data  PHP can send and receive cookies  PHP can add, delete, modify data in your database  PHP can restrict users to access some pages on your website  PHP can encrypt data  With PHP you are not limited to output HTML. You can output images, PDF files, and even Flash movies. You can also output any text, such as XHTML and XML

9. What is a PHP File?  PHP files can contain text, HTML, JavaScript code, and PHP code  PHP code are executed on the server, and the result is returned to the browser as plain HTML  PHP files have a default file extension of ".php”

10. What you need to start using PHP ? Installation You will need 1. Web server ( Apache ) 2. PHP ( version 5.3) 3. Database ( MySQL 5 ) 4. Text editor (Notepad) 5. Web browser (Firefox ) 6. www.php.net/manual/ en/install.php www.php.net/manual/ en/install.php

11. Syntax PHP code  A PHP script can be placed anywhere in the document.  A PHP script starts with

12. Syntax PHP code Standard Style : Short Style: Script Style: ASP Style:

13. Echo  The PHP command ‘echo’ is used to output the parameters passed to it.  The typical usage for this is to send data to the client’s web- browser void echo (string arg1 [, string argn...])  Syntax : void echo (string arg1 [, string argn...])  In practice, arguments are not passed in parentheses since echo is a language construct rather than an actual function

14. Echo - Example  <?php echo “ This my first statement in PHP language“;  ?>

15. Print  print is not actually a real function (it is a language construct) so you are not required to use parentheses with its argument list. <?php print("Hello World"); ?>

16. Echo Vs Print Improve this chartEchoPrint Parameters:echo can take more than one parameter when used without parentheses. The syntax is echo expression [, expression[, expression]... ]. Note that echo ($arg1,$arg2) is invalid. print only takes one parameter. Return value:echo does not return any valueprint always returns 1 (integer) Syntax:void echo ( string $arg1 [, string $... ] )int print ( string $arg ) What is it?:In PHP, echo is not a function but a language construct. In PHP, print is not a really function but a language construct. However, it behaves like a function in that it returns a value.

17. Variables  As with algebra, PHP variables can be used to hold values (x=5) or expressions (z=x+y).  Variable can have short names (like x and y) or more descriptive names (age, carname, totalvolume).  Rules for PHP variables:  A variable starts with the $ sign, followed by the name of the variable

18. Variables  A variable name must begin with a letter or the underscore character  A variable name can only contain alpha-numeric characters and underscores (A-z, 0-9, and _ )  A variable name should not contain spaces  Variable names are case sensitive ($y and $Y are two different variables)

19. Variables  Case-sensitive ($Foo != $foo != $fOo)  Global and locally-scoped variables  Global variables can be used anywhere  Local variables restricted to a function or class  Certain variable names reserved by PHP  Form variables ($_POST, $_GET)  Server variables ($_SERVER)

20. Creating (Declaring) Variables <?php $name = “ali” echo( $name); ?>

21. Creating (Declaring) Variables  PHP has no command for declaring a variable.  A variable is created the moment you first assign a value to it:  After the execution of the statements above, the variable txt will hold the value Hello world!, and the variable xwill hold the value 5.  Note: When you assign a text value to a variable, put quotes around the value. $txt="Hello world!"; $x=5;

22. Variables <?php $name = “ali”; $age = 23; echo “ My name is $name and I am $age years old”; ?>

23. PHP is a Loosely Typed Language  In the example above, notice that we did not have to tell PHP which data type the variable is.  PHP automatically converts the variable to the correct data type, depending on its value.  In a strongly typed programming language, we will have to declare (define) the type and name of the variable before using it.

24. Variables <?php $name = 'elijah'; $yearborn = 1975; $currentyear = 2005; $age = $currentyear - $yearborn; echo ("$name is $age years old."); ?>

25. Variables A simple PHP document Welcome to PHP, !

26. PHP Variable Scopes  The scope of a variable is the part of the script where the variable can be referenced/used.  PHP has four different variable scopes:  local  global  static  Parameter - In chapter function we will talk about theme.

27. String Variables in PHP  string variables are used for values that contain characters.  After we have created a string variable we can manipulate it. A string can be used directly in a function or it can be stored in a variable.  In the example below, we create a string variable called txt, then we assign the text "Hello world!" to it. Then we write the value of the txt variable to the output:

28. PHP strings can be specified in four ways  Single quoted strings will display things almost completely "as is." Variables and most escape sequences will not be interpreted. The exception is that to display a literal single quote, you can escape it with a back slash \', and to display a back slash, you can escape it with another backslash \\ (So yes, even single quoted strings are parsed). Single quoted strings <?php $txt = ‘my string ‘; echo $txt; // my string ?> <?php $txt = ‘my string ‘; echo ‘$txt’; // $txt ?>

29. PHP strings can be specified in four ways  Double quote strings will display a host of escaped characters (including some regexes), and variables in the strings will be evaluated. An important point here is that you can use curly braces to isolate the name of the variable you want evaluated. For example let's say you have the variable $type and you what to echo "The $types are" That will look for the variable $types. To get around this use echo "The {$type}s are" You can put the left brace before or after the dollar sign. Take a look at string parsing to see how to use array variables and such. Double quote stringsstring parsing <?php $txt = “my string”; echo $txt; // my string ?> <?php $txt = “my string “; echo “$txt”; // my string ?>

30. PHP strings can be specified in four ways  Heredoc string syntax works like double quoted strings. It starts with <<<. After this operator, an identifier is provided, then a newline. The string itself follows, and then the same identifier again to close the quotation. You don't need to escape quotes in this syntax. Heredoc  Nowdoc (since PHP 5.3.0) string syntax works essentially like single quoted strings. The difference is that not even single quotes or backslashes have to be escaped. A nowdoc is identified with the same <<< sequence used for heredocs, but the identifier which follows is enclosed in single quotes, e.g. <<<'EOT'. No parsing is done in nowdoc. Nowdoc

31. PHP strings can be specified in four ways  Heredoc Heredoc <?php $name='MyName'; echo <<<EOT My name is "$name". I am printing some A Now, I am printing some {A}. This should print a capital 'A': \x41 EOT; ?> My name is "MyName". I am printing some A Now, I am printing some {A}. This should print a capital 'A': A

32. PHP strings can be specified in four ways  Nowdoc Nowdoc <?php $name='MyName'; echo <<<'EOT' My name is "$name". I am printing some A Now, I am printing some {A}. This should print a capital 'A': \x41 EOT; ?> My name is "$name". I am printing some A Now, I am printing some {A}. This should print a capital 'A': \x41

33. Single & Double Quotes <?php echo “ Hello world ”; echo ‘ Hello world’; ?>

34. Single & Double Quotes <?php $word = ‘ World’; echo “ Hello $word ”; echo ‘ Hello $word ’; ?>

35. Comments in PHP // or # for single line /* */ for multiline /* this is my comment one this is my comment two this is my comment three */

36. Whitespace You cant have any whitespace between <? and php. You cant break apart keywords (e.g :whi le,func tion,fo r) You cant break apart varible names and function names (e.g:$var name,function f 2)

37. The PHP Concatenation Operator  here is only one string operator in PHP.  The concatenation operator (.) is used to join two string values together.  The example below shows how to concatenate two string variables together:

38. The PHP Concatenation Operator <?php $string1=“Hello”; $string2=“PHP”; $string3=$string1. “ ”. $string2; Print $string3; ?> Hello PHP

39. Escaping the Character If the string has a set of double quotation marks that must remain visible, use the \ [backslash] before the quotation marks to ignore and display them. <?php $heading="\"Computer Science\""." "; $heading1=@"Computer Science"; echo $heading; echo $heading1; ?> "Computer Science" Computer Science

40. Example Notice how echo ‘5x5=$foo’ outputs $foo rather than replacing it with 25 Strings in single quotes (‘ ’) are not interpreted or evaluated by PHP This is true for both variables and character escape-sequences (such as “\n” or “\\”) <?php $foo = 25;// Numerical variable $bar = “Hello”;// String variable echo $bar;// Outputs Hello echo $foo,$bar;// Outputs 25Hello echo “5x5=”,$foo;// Outputs 5x5=25 echo “5x5=$foo”;// Outputs 5x5=25 echo ‘5x5=$foo’;// Outputs 5x5=$foo ?>

41. Data type

42. Get type  gettype — Get the type of a variable  Returns the type of the PHP variable var. <?php $a = 1; $b = 1.2; $c = "abc"; echo gettype($a)." "; echo gettype($b)." "; echo gettype($c)." "; ?> integer double string

43. Set type

44. Set type <?php $testString = “10.2abc”; // call function settype to convert variable // testString to different data types print( "$testString" ); settype( $testString, "double" ); print( " as a double is $testString " ); print( "$testString" ); settype( $testString, "integer" ); print( " as an integer is $testString " ); settype( $testString, "string" ); print( "Converting back to a string results in $testString " ); ?> 10.2abc as a double is 10.2 10.2 as an integer is 10 Converting back to a string results in 10

45. Casting Data type <?php $data = "98.6 degrees"; echo "Now using type casting instead: "; echo "As a string - ".(string) $data ; echo " As a double - ".(double) $data; echo " As an integer - ".(integer) $data; ?> Now using type casting instead: As a string - 98.6 degrees As a double - 98.6 As an integer - 98

46. Casting Data type <?php $data = "98.6 degrees"; echo "Now using type casting instead: "; echo "As a string - ".(string) $data ; echo " As a double - ".(double) $data; echo " As an integer - ".(integer) $data; ?> $variable = (datatype) $variable or value

47. Casting Data type <?php $a = “ 12.4 abc” echo (int) $a; echo (double) ($a); echo (float) ($a); echo (string) ($a); ?>

48. PHP Operators The assignment operator = is used to assign values to variables in PHP. The arithmetic operator + is used to add values together in PHP. Assignment operators Syntactical shortcuts Before being assigned values, variables have value undef Constants Named values define function

49. PHP Operators Arithmetic Operators Assignment Operators Incrementing/Decrementing Operators Comparison Operators Logical Operators

50. Arithmetic Operators OperatorNameDescriptionExampleResult x + yAdditionSum of x and y2 + 24 x - ySubtractionDifference of x and y5 - 23 x * yMultiplicationProduct of x and y5 * 210 x / yDivisionQuotient of x and y15 / 53 x % yModulusRemainder of x divided by y5 % 2 10 % 8 10 % 2 120120 - xNegationOpposite of x- 2 a. bConcatenationConcatenate two strings"Hi". "Ha"HiHa

51. Assignment Operators AssignmentSame as...Description x = y The left operand gets set to the value of the expression on the right x += yx = x + yAddition x -= yx = x - ySubtraction x *= yx = x * yMultiplication x /= yx = x / yDivision x %= yx = x % yModulus a.= ba = a. bConcatenate two strings

52. Arithmetic Operations $a - $b // subtraction $a * $b// multiplication $a / $b// division $a += 5// $a = $a+5 Also works for *= and /= <?php $a=15; $b=30; $total=$a+$b; echo $total; echo“ $total ”; // total is 45 ?>

53. Incrementing/Decrementing Operators OperatorNameDescription ++ xPre-incrementIncrements x by one, then returns x x ++Post-incrementReturns x, then increments x by one -- xPre-decrementDecrements x by one, then returns x x --Post-decrementReturns x, then decrements x by one

54. Arithmetic Operations <?php $a =1; echo $a++; // output 1,$a is now equal to 2 echo ++$a; // output 3,$a is now equal to 3 echo --$a; // output 2,$a is now equal to 2 echo $a--; // output 2,$a is now equal to 1 ?>

55. Arithmetic Operations <?php $num1 = 10; $num2 =20; // addition echo $num1+$mum2. ‘ ’; //subtraction echo $num1 - $num2. ‘ ’; // multiplication ?>

56. Arithmetic Operations <?php // Multiplication echo $num1* $num2. ‘ ’; // Division Echo $num1/num2. ‘ ’ ; //increment $num1++; $Num2--; Echo $num1; ?>

57. Arithmetic Operations <?php $a =(int)(‘test’); // $a==0 echo ++$a; ?>

58. Dumps information about a variable  This function displays structured information about one or more expressions that includes its type and value. Arrays and objects are explored recursively with values indented to show structure. void var_dump ($expression [,... ] ) <?php $b = 3.1; $c = true; var_dump($b); var_dump($c); //or var_dump($b,$c); ?> float 3.1 boolean true

59. Comparison Operators OperatorNameDescriptionExample x == yEqualTrue if x is equal to y5==8 returns false x === yIdenticalTrue if x is equal to y, and they are of same type 5==="5" returns false x != yNot equalTrue if x is not equal to y5!=8 returns true x <> yNot equalTrue if x is not equal to y5<>8 returns true x !== yNot identicalTrue if x is not equal to y, or they are not of same type 5!=="5" returns true x > yGreater thanTrue if x is greater than y5>8 returns false x < yLess thanTrue if x is less than y5<8 returns true x >= yGreater than or equal toTrue if x is greater than or equal to y5>=8 returns false x <= yLess than or equal toTrue if x is less than or equal to y5<=8 returns true

60. Comparison Operators <?php var_dump(0 == "a"); // 0 == 0 -> true var_dump("1" != "01"); // 1 != 1 -> false var_dump("10" == "1e1"); // 10 == 10 -> true var_dump("10" == "1ee1"); // 10 == 1 -> false var_dump(100 === "100"); // 100 == 100 -> false var_dump("100" === "100"); // 100 == 100 -> true ?> boolean true boolean false boolean true boolean false boolean true

61. Logical Operators OperatorNameDescriptionExample x and yAndTrue if both x and y are truex=6 y=3 (x 1) returns true x or yOrTrue if either or both x and y are truex=6 y=3 (x==6 or y==5) returns true x xor yXorTrue if either x or y is true, but not bothx=6 y=3 (x==6 xor y==3) returns false x && yAndTrue if both x and y are truex=6 y=3 (x 1) returns true x || yOrTrue if either or both x and y are truex=6 y=3 (x==5 || y==5) returns false ! xNotTrue if x is not truex=6 y=3 !(x==y) returns true

62. Logical Operators <?php $a = (false && true); $b = (true || false); $c = (false and flase); $d = (true or true); $e = false || true; $f = false or true; var_dump($e, $f); $g = true && false; $h = true and false; var_dump($g, $h); ?> boolean true boolean false boolean true

63. Define function - constant VALUE  Variable name as string : the name of variable in single or double quotation. <?php define(‘variable ’,10); echo variable ; //10 ?> define( variable name as string, value );

64. Define function - constant VALUE <?php $a = 5; print( "The value of variable a is $a " ); // define constant VALUE define( "VALUE", 5 ); // add constant VALUE to variable $a $a = $a + VALUE; print( "Variable a after adding constant VALUE is $a " );

65. Define function - constant VALUE // multiply variable $a by 2 $a *= 2; print( "Multiplying variable a by 2 yields $a " ); // test if variable $a is less than 50 if ( $a < 50 ) print( "Variable a is less than 50 " ); // add 40 to variable $a $a += 40; print( "Variable a after adding 40 is $a " ); // test if variable $a is 50 or less if ( $a < 51 ) print( "Variable a is still 50 or less " ); // test if variable $a is between 50 and 100, inclusive elseif ( $a < 101 ) print( "Variable a is now between 50 and 100, inclusive " ); else print( "Variable a is now greater than 100 " );

66. // print an uninitialized variable print( "Using a variable before initializing: $nothing " ); // add constant VALUE to an uninitialized variable $test = $num + VALUE; print( "An uninitialized variable plus constant VALUE yields $test " ); // add a string to an integer $str = "3 dollars"; $a += $str; print( "Adding a string to variable a yields $a " ); ?> Define function - constant VALUE

67. Referencing Operators  We know the assignment operators work by value,by copy the value to other expression,if the value in right hand change the value in left is not change.  Ex: <?php $a =10; $b =$a; $b =20 Echo $a; // 10 ?>

68. Referencing Operators  But we can change the value of variable $a by the reference, that mena connect right hand to left hand,  Example: <?php $a =10; $b = &$a; $b= 20; echo $a; // 20 ?>

69. PHP Conditional Statements  Very often when you write code, you want to perform different actions for different decisions. You can use conditional statements in your code to do this.  In PHP we have the following conditional statements:  if statement - executes some code only if a specified condition is true  if...else statement - executes some code if a condition is true and another code if the condition is false  if...else if....else statement - selects one of several blocks of code to be executed  switch statement - selects one of many blocks of code to be executed

70. The if Statement The if statement is used to execute some code only if a specified condition is true. hello john if (condition) { code to be executed if condition is true; }

71. The if...else Statement Use the if....else statement to execute some code if a condition is true and another code if the condition is false. if (condition) { code to be executed if condition is true; } else { code to be executed if condition is false; }

72. The if...else Statement Have a good night!

73. The if...else if....else Statement Use the if....else if...else statement to select one of several blocks of code to be executed. if (condition) { code to be executed if condition is true; } else if (condition) { code to be executed if condition is true; } else { code to be executed if condition is false; }

74. The if...else if....else Statement <?php $t=7; if ($t<10) { echo "Have a good morning!"; } else if ($t<20) { echo "Have a good day!"; } else { echo "Have a good night!"; } ?> Have a good morning!

75. The switch Statement Use the switch statement to select one of many blocks of code to be executed. switch (n) { case label1: code to be executed if n=label1; break; case label2: code to be executed if n=label2; break; default: code to be executed if n is different from both label1 and label2; }

76. The switch Statement Your favorite color is red!

77. PHP Loops Loops execute a block of code a specified number of times, or while a specified condition is true. In PHP, we have the following looping statements: while - loops through a block of code while a specified condition is true do...while - loops through a block of code once, and then repeats the loop as long as a specified condition is true for - loops through a block of code a specified number of times foreach - loops through a block of code for each element in an array

78. The while Loop The while loop executes a block of code while a condition is true. while (condition) { code to be executed; } "; $i++; } ?> The number is 1 The number is 2 The number is 3 The number is 4 The number is 5

79. The do...while Statement The do...while statement will always execute the block of code once, it will then check the condition, and repeat the loop while the condition is true. do { code to be executed; } while (condition); "; } while ($i The number is 2 The number is 3 The number is 4 The number is 5 The number is 6

80. The do...while Statement "; } while ($i The number is 2 The number is 3 The number is 4 The number is 5 The number is 6

81. The for Loop The for loop is used when you know in advance how many times the script should run. Parameters: init: Mostly used to set a counter (but can be any code to be executed once at the beginning of the loop) for (init; condition; increment) { code to be executed; }

82. The for Loop condition: Evaluated for each loop iteration. If it evaluates to TRUE, the loop continues. If it evaluates to FALSE, the loop ends. increment: Mostly used to increment a counter (but can be any code to be executed at the end of the iteration) Note: The init and increment parameters above can be empty or have multiple expressions (separated by commas).

83. The for Loop "; } ?> The number is 1 The number is 2 The number is 3 The number is 4 The number is 5

84. The foreach Loop The foreach loop is used to loop through arrays. We well talk about this in chapter array

85. Isset Function bool isset ( $var ) Determine if a variable is set and is not NULL. If a variable has been unset with unset(), it will no longer be set. isset() will return FALSE if testing a variable that has been set to NULL. Also note that a NULLbyte ("\0") is not equivalent to the PHP NULL constant. If multiple parameters are supplied then isset() will return TRUE only if all of the parameters are set. Evaluation goes from left to right and stops as soon as an unset variable is encountered.

86. Isset Function <?php $var = ''; // This will evaluate to TRUE so the text will be printed. if (isset($var)) { echo "This var is set so I will print."; } ?>

87. Unset Function void unset ( $var) unset() destroys the specified variables. The behavior of unset() inside of a function can vary depending on what type of variable you are attempting to destroy. If a globalized variable is unset() inside of a function, only the local variable is destroyed. The variable in the calling environment will retain the same value as before unset() was called.

88. unset Function <?php $foo = 'bar'; echo $foo; unset($foo); echo $foo; ?>

89. Info PHP Page <?php phpinfo(); ?>

90. Goto

91. Chapter Example

92. if/else if/else statement <?php if ($foo == 0) { echo ‘The variable foo is equal to 0’; } else if (($foo > 0) && ($foo <= 5)) { echo ‘The variable foo is between 1 and 5’; } else { echo ‘The variable foo is equal to ‘.$foo; } ?>

93. Switch Statment <?php $count=0; switch($count) { case 0: echo “hello PHP3. ”; break; case 1: echo “hello PHP4. ”; break; default: echo “hello PHP5. ”; break; } ?> hello PHP3

94. Switch - Example <?php $total = 0; $i = 2; switch($i) { case 6: $total = 99; break; case 1: $total += 1;break; case 2:$total += 2;break; case 3: $total += 3; ;break; case 4:$total += 4; break; default : $total += 5;break; } echo $total; ?> 2

95. For Loop <?php $count=0; for($count = 0;$count <3,$count++) { Print “hello PHP. ”; } ?> hello PHP. hello PHP. hello PHP.

96. For - Example <?php for ($i = 1; $i <= 10; $i++) { echo $i; } ?>

97. For-Example <?php $brush_price = 5; echo " "; echo " Quantity "; echo " Price "; for ( $counter = 10; $counter <= 100; $counter += 10) { echo " "; echo $counter; echo " "; echo $brush_price * $counter; echo " "; } echo " "; ?>

98. While Loop <?php $count=0; while($count<3) { echo “hello PHP. ”; $count += 1; // $count = $count + 1; // or // $count++; } ?> hello PHP. hello PHP. hello PHP.

99. While - Example <?php $i = 0; while ($i++ < 5) { echo “loop number : “.$i; } ?>

100. Do... While Loop <?php $count=0; do { echo “hello PHP. ”; $count += 1; // $count = $count + 1; // or // $count++; } while($count<3); ?> hello PHP. hello PHP. hello PHP.

101. Do..While 0); ?>

102. For..If '; for($i = 0; $i '. $i. ' '; if(($i + 1) % $rows == 0){ echo ' '; } } echo ' '; ?>

103. For "; } ?>

104. Nested For

105. While - Switch <?php $i = 0; while (++$i) { switch ($i) { case 5: echo "At 5 \n"; break 1; /* Exit only the switch. */ case 10: echo "At 10; quitting \n"; break 2; /* Exit the switch and the while. */ default: break; } } ?>

106. Continue

107. If - Switch <?php $i = 1; if ($i == 0) { echo "i equals 0"; } elseif ($i == 1) { echo "i equals 1"; } elseif ($i == 2) { echo "i equals 2"; } switch ($i) { case 0: echo "i equals 0"; break; case 1: echo "i equals 1"; break; case 2: echo "i equals 2"; break; } ?>

108. Do..While - IF

109. If in other style